Indicator setting mechanism operable by means of character comparisons



INDICATOR SEETTING MECHANISM OPERABLE BY MEANS OF CHARACTER COMPARISONS Filed Sept. 20, 1949 3 Sheets-SheeiJ Sept. 2, 1952 J c. MARSHALL ETAL 2,609,439

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\F v M if V'- A INVENTORS c3 V V V JOSEPH c. MARSHALL p JOHN J. CONNOLLY smc'e nzconoms TO secouonavvsronsa BY a T V L T mum nzcoaomc ATTORN EY 3 Sheets-Sheet 2 INVENTORS ATTORNEY CHECK-BACK KEY JOSEPH CV MARSHALL JOHN J. CONNOLLY I -IOOV MARSHALL EI'AL INDICATOR SETTING MECHANISM OPERABLB BY MEANS OF CHARACTER COMPARISONS MARK I NAL SPACE Sept. 2, 1952 Filed-Sept. 20, 1949 ATA 600E FIVE STAGE COUNTING RING "IOOV 3 snow. 11-- MARK -IOOV J. c. MARSHALL ET AL INDICATOR SETTING MECHANISM OPERABLE BY MEANS OF CHARACTER COMPARISONS 3 Sheets-Sheet 3 Filed Sept. 20, 1949 T SPACE SIGNAL o'nien RR 00 TT AG m DE W5 8 H A a COM PARATO RS INVENTORS JOSEPH C. MARSHALL JOHN J. CONNOLLY ATTOR N EY Patented Sept. 2, 1952 UNITED STATES PATENT OFFICE "mnrchron gsa'r'rmo MECHANISM dran- ABLE B Y "MEANS or CHARACTER COM- PARISONS Joseph CsMai-shall, Baldwin,- and John J. Connolly, New York, N. Y., assignors toThe Teleregister Corporation, New York, N. Y., a corporation 01 Delaware Application September 20, 1949, Serial-No.116fi52 11' Claims. (01; 177-353) rhieator'posting controlsignals, we have-adopted the technique of first storing the signals on a magnetic drum or tape, then utilizing an iterative read-out oi. the signalsto trigger certain control mechanism having as its function to opcrate an indicator stepping device for moving "mt indicator from one step to another, this oporation being repeated as many times as may be necessary to step the indicator from its previous posting; position to a new postingposition.

invention is intended to be used under conditionswhich may be similar to those dein a patent of Harold F. May, -No. 3,564,403, issued August 14, 1951. In May's disthe system describedhad a'very difiermode of operation from the --onewhich we shall set forth in this case. May, in his system, -!Bquires the use of certain components which we have iound'unnecessary to employ. vThecircult arrangement which will presently be described isone that lends itself to more rapid operation and provides other advantages as well. Wehave also disclosed an arrangement-for reporting-back to the source of signalsa-read-out oi the indicator settings for which the original signals may'hav'e been-transmitted in the first place; check-back system, insofar as-we are were, is which possesses numerousznov'el 'eq'iects;

li'i describing 'ourinirentionwe shall cover'gen- 'erally a method of first recording'the received 'oignais ana magnetic storage medium and then producing a read-out of these reeoi'ded'signals under control-of synchronous pulses. A comober'atiriginie's'ponse' to marking code elementssensed 'n cm the read-out and in resecasecemaicatcnuenved space oueelements nitiates anin'dioator operation whenever the the storecl sighal faii to dovetail with spacing elements of a code represents the indicators position of orientation. We wish it to be understood, however that -pur invention may be practiced independently oi a magnetic storage medium, provided the signals can be iteratively transmittcd angl received at a fixed cadence so as to enablacyclical operation-oi the various parts ot-the system which must be sequentially operated; The use of a constantly revolving drum have arecording path for the data signals and another recordpath from which synchronizingpulses may be derived at a fixed cadence illustrates, iii-simplefashion.

how :the signals'may best be translated intddndicator setting pulses. This is especially true'in respect to systems in which a plurality ot'indicators is used. 5,.

It is an object of our invention to ,provide translating means and an indicator setting circuit" arrangement which will handle incoming code signals, or signals derived from a magnetic drum at a very rapid rate, and which Walton currently set and reset different indicator units in accordance with the read-out of information from a magnetic drum.

Another object of our invention is-"to proyide an indicator posting mechanism and a circuit arrangement therefor, in combination with a magnetic data storage drum with associated recording and reading heads,-the novel portibns of the system including means for making parisons between two code -combinationsfone of which, on thewone hand, is represented by the read-out from magnetic storage of a 5-unit c'odejand on the other hand, a code representation corresponding to the current setting of-an indicator drum. a

Still another object of our invention is to brovide a commutator and-brush arrangement associated with each indicator of a posting board. this arrangem'entbeing adapted to present for comparison purposes the necessary 'elementsoi a code combination so that a signal to be utilized for posting purposes, lacking agreement there with, will effect a setting operation'upon the in. dicator tog-ive it one step.

:Another' object of our inventionrelate's to improvemen'ts in systems'for transmitting achecltback signal to the original source bi the post ing signais for the purpose of com aringtneset ting of each indicator in the posting board with a record at said source.

In carrying out our invention, we have found it desirable to use what is known as a safety code. This is a code wherein each permutation has a uniform number of marking elements and a uniform number of spacing elements. The advantages of using this code are that any mutilation of the code which may be caused, say, by a static pulse in radio transmission, will immediately become apparent and will avoid misleading anyone who might otherwise read an erroneous setting of the indicator. In the system as herein illustrated, the transmission of a -unit code containing more than three markingelements would result in the failure of the selected indicator to come to rest. This continuous response to'the mutilated signal in an attempt to find a resting point would give warning that the posting signal should be repeated correctly.

Another feature of our invention relates to the use of a comparator for determining when an indicator should be reset to agree with a magnetically stored signal. Our preferred comparator checks the code elements serially. Any failure of'correspondence between the stored signal and the current indicator setting must result in control of the setting mechanism to rotate the indicator one step. Further steps may be taken for cyclically advancing the indicator into a position corresponding to the significance of the incoming code signal. 7

, Ourinvention will now be described in more detail, reference being made to the accompanying in which:

Figs. 1, 2 and 3 taken together and laid in the order named from left to right, represent a schematic circuit diagram of electrically and cyclically operable posting means of the type herein above described,

'Fig. 4 is a chart of code signals which may be suitably employed for transmission of statistical data, storage thereof in a magnetic storage medium, and application from the storage medium to a comparator which in turn may be used to apply posting signals to one or more settable indicators, and

' Fig; 5 is a timing diagram showing certain relationships of sequential operation with respect to diilerent components of the electronic circuit of our posting system.

The data storage device This disc or recording path I is utilized for synchronizing purposes and will therefore be assumed to have a record thereon of evenly-spaced spots of magnetization so that synchronizing pulses may be generated in a, reading head 6 and applied therefrom to an amplifier I. The output from amplifier I consistsof'sine wave pulses.

The disc or recording path '3 serves for the storage of data which may be applied thereto by a recording head 8 under control of incoming signalsgfrom any desired source. It will be under- 4 stood that such signals may be recorded fro time to time in accordance with any changes of statistical data and they are to be manifested as resettings of the indicators in a posting board. New recordings automatically erase old recordings when the applied magnetizing effect is strong enough to produce saturation of the lines of force in the spot areas of the recording path.

Immediately upon making any new recording on the element 3 it will be read out by a reading head 9 which will hereinafter be considered as the source of intelligence to be manifested on the indicator. A single train of 5-unit code signals may be recorded on the circumference of the disc or drum 3 and the position of orientation of each code signal will have reference to a particular indicator unit among as many such units as are comprehended in the posting board. A posting board of very large capacity, however, may utilize a plurality of recording paths 3 for diiferent groups of indicators, each record path having operatively associated with it a different one of several reading heads 9.

The recording unit 2 serves for check-back purposes and has operatively associated with it a recording head l0 and .a reading head I I. We shall again refer to these components .2, I0 and I I when describing the check-back system in more detail.

An amplifier and discriminator unit I2 is shown to be controlled by the reading head 9 and will be understood to be of any well-known type such as to deliver a semi-cycle pulse output, the oppositely poled semi-cycles being suppressed. This discriminator delivers output pulses of negative polarity and they represent mark elements of the signal. In the absence of a pulse a space element is represented.

The indicw'tor units In Fig. 3 we haveshown several commutatorand-brush arrangements'lii, I311, I31: and I3c' in developed form. Each of the indicator units to be comprised in a posting board is provided with a segmented commutator having, as shown, ten segments Which are numbered from 1 to 9 inclusive and 0, or, as in the case of. commutator I30, the segments may represent the series 1 to 5 inclusive and the letters B, X, Q, R Z. Any other letters may be chosenat will, if desired. These are simply illustrative markings that may be displayed by diflerent orientations of a rotatable indicator.

Either the commutator I3 or the brushes I4 and I5 may be made rotatable with an indicator drum. In order to use the code combinations of a safety code such as shown in Fig, 4, it is essential that the brushes I4 and I5 shall rest upon adjacent segments of the commutator l3. Other codes, however, may be devised wherein the brushes need not rest upon adjacent segments.

The posting system as herein shown will be understood to include seven indicators for which the commutator and brush arrangement of indicators #I, #6 and #1 are drawn out in detail in Fig. 3, while the remaining 4 indicator units will be understood to be of the same type and character and are merely indicated as present in the space labelled Illa. The segments of the commutator are multiple-wired to buses I3, each of which corresponds to one of the elements of a code combination. The uppermost conductor in the group I6 may be considered to correspond with the first code element of a code signal, and the bottom-most bus is the 5th codeelement nator unit l2.

- to those of tubes H and I. In other words, when tube J, normally blocked on its left side, is rendered-conductive by a positive pulse from the stage of counting ring 23, the right hand side of tube J becomesmomentarily blocked.

The selfe-restoration of tube J after .a certain delay period results in the restoration of a blocked state on the left side and the delivery of a positive pulse which is applied through capacitor 30 to the control grid of cathode follower tuke K. The cathode in tube K is then driven to a positive value. A resistor 3| is common to the cathodes on the left-hand side of each of the stages of counting ring 22, and to the oathode of tube K. These left-hand cathodes in ring 22 are, therefore, raised to a potential which is high relative to their associated grids. Any flipfiop stage the left side of which was at that moment conductive will now be blocked. No change will occur in the other stages, except the stage next following, this stage being then triggered by the positive output pulse from the preceding stage. Thus, it will be seen that upon completion of each count of 5 synchronizing pulses by the counting ring 23, the 7-stage counting ring 22 will receive a counting pulse and will advance its count representation.

The comparator Each of the left-hand anodes of the digital stages in counting ring 22 has a separate connection through cable Y to diflerent ones of a plurality of gate tubes 8 and 43, and to the right-hand grids therein. So tubes S and 43 are progressively conditioned while the 7-stage counting ring 22 takes its counting steps. The conditioning is to select one at a time of tubes 8 and 43 to act as a gate, provided that they simultaneously receive a negative (mark) message signal pulse U from the amplifier and discriminator unit l2.

Twin triode tube S is individual to the setting mechanism for one particular indicator. This tube has associated with it a gaseous comparator tube T whichis of the tetrode type. Tube T is triggered under simultaneous control by potentials applied to its #1 and #2 grids. Its #1 grid is connected to' the brushes I4 and I5 of the commutator-brush arrangement associated with the indicator in question. Its #2 grid is normally connected to the anodes of tube S and is driven positive when tube 8 is completely blocked. The

tripping of tube S is perfected by the application ofa steady cut-offbias potential applied to the gridof its right-hand triode section whenever it is selected by one of the stages of the 7-stage counting ring 22.

Whenreadinghead 9 reads the stored signals from the magnetic storage medium 3 they are applied'as input to the amplifier and discrimi- The output from this unit is a negative pulse which represents a mark element of the code signal. Thisnegative pulse is labeled U and is applied directly to the control grid in the left-hand triode section of tube S. The negative bias potential, say from stage I of the counting ring 22, is labeled Y and is applied to the control grid in the right-hand triode section of tube 8. 1

The effect of cutting on tube S is, therefore, to apply a positive pulse from its common anode connection through one of the conductors in cable 3| and thence through one of the movable contacts and a back contact of relay 32 to a conductor in cable 33 which leads to the #2 gridintube T.- The pulse which is transmitted 8 through this circuit has been labeled Z and represents the application to the tube T of a marl! element of a code signal.

Whenever a space-element of a code signal as recorded on the magnetic storage medium 3 is read out, its eflect is suppressed in the amplifier and discriminator unit l2. Consequently, it will be skipped during the counting pulse periods as defined by the counting ring 23. In this case, tube S will not be completely cut off and the voltage applied to the #2 grid of tube T will remain below the ignition level.

It was mentioned above that the counting ring 23 counts the delayed synchronizing pulse output from the cathode follower tube I; also that buses it are successively energized with high anode potentials as the count progresses from "1" through 5. If either of the brushes l4 or II happens to rest on a segment I3 when the latter receives a positive pulse from the counting ring 23, then such a pulse is fed through conductor l8, l3 and a resistor 20 and is applied to the #1 grid of tube T for purposes of comparison with a simultaneous application of a markpulse to the #2 grid of tube T, as derived from tube 8.

The triggering of tubes T and 44 is to be performed only when a mark signal element derived from the magnetic storage device and a space signal element derived from a commutator-brush arrangement'occur simultaneously; that is, when the code patterns fail to dovetail. Conversely, if the two code patterns are in agreement, then, for each of the five code elements as defined by the counting ring 23, one or the other of the two grids in tube T will be driven positive, but not both together. In this event tube T or one of tubes 44 will not be triggered during any one of the five counts of the counting ring 23, which would mean that the indicator is then set to a position to indicate the significance of the stored signal.

The purpose of the one-way conductors or rectifiers I1 is to avoid improper feed-back of positive pulses from one to another of the buses I6. Such positive pulses emanate from the left side of the particular counting stage which represents the instant count from 1 to 5. On each of these counts, two non-adjacent segments of each commutator distributor are raised to a high potential level. For the #1 count the segments are I andfi, for the #2 count they are 2 and 9, for the #3 count they are 3 and l, for the #4 count they are 4 and 0, and for the #5 count they are 3 and 8. Brushes l4 and I5 move together over adjacent pairs of segments whenever the stepping mechanism of the indicator is actuated.

If the settings of brush I4 on each of the numbered segments of commutator l3 be referred to the code chart of Fig. 4, it will be seen that each of the ten code patterns for the different indicator settings provides a location for two code elements of space significance on the two adjacent-segments l3 which are contacted by the two brushes l4 and I 6. So the standing of brushes I land I5 on two adjacent commutator segments may be considered to represent space elements of a permutation code. Three other segments, in addition to these two on which the marking elements of the code.

Our method of making direct comparisons between the code representation of the brushes and the code signal elements derived from magnetic storage includes sequential testing of the difrem'eddeeiemente Iron; 1- to 5 as'the countin nip through itscycl'e; at' a'ny point 1e codes-donot-ajgrec, then tub''T is tri g :r'edami eauses a pulse to be transmitted-to the mgnet or the stepping mechamsmi thereby Bing -the indicator tomove through-enemy); Ihe'n this comparison "operationm repeated -a :flicient number 01- timeete st'ep the indicator round' andthus to Bringabout-an agreement etweenthe two..-codes, it will, be found that the v brushes l4 and I rest upon segments which ave'a'r space significance and whioh provide a entailing of space-pulses withmark pulsesae piilied to'grids'm and #S'ofmbe 'I At-this meibher torey the indicator willcom e' wrest ad "will remain so' set until some difleren't co'de-=-' gait; isrread outfibnr magnetic storage 'Ihecadence of" operatione of the step'iiing teem determined by the revelation-s ace I themae fleti'c etorafe Ember; No more than me devbiutiohsere nccessai yiorany complete :tting 01 an indicator. During any one revoiuon: however; it is moss-me to provide single sttflig' 'eteptibr each one-o1 the indicators. My

Itwiii be" noted'that-compariion's are made only" themarkelements of the magneticallye me I and i space 1 elements as defined by- [reorientation of the Brushes wane: 5 withrep068 to= thecommutatom it; The marh-r'epre entifig-" positiohs oi the commutator segments annot be compared mth sjpaee signal'sfrom:

Storage, and th'ere is nb noed to do so, ratified-theta safety eedo such es shown 'in I85 4 1: mulled;

Anmher'matter to benoted ie-thah in*makingmieeo'ode signal competition-'-iais above 'de cubed; there may be two points ot- 'eoinctdence etween a marweiemontof the'storcd'sishai angi spue 'eiement-of the brush s'etting'. -Under mfiml cmemtirig conditions; however; the two ofimdcnces "occurring im a single-scanning at he fl've'element'soi a 'code signai wo'uld' b'e in- 898111617! generating-two discret piils'e's of but-' rut'di omthe g'aaeoas'tube'r. At practical speeds I scanning each oode eiement' may he scanned n approximately two miiliseeonds -or 1e'ss.' .hordnoze the uan" lapse" of time betvqeena wo' eomeidences 1s '-8"miiiiseconds, which is not to ailow ntinguishi'nmthe gaseous Marge b'eiore the see'end-Aattempt to ignite 3 :othe somemechanism-manner auowed to: metep*durin g s ingle "revomtion 'er thc fiiag leuc The check-back system In some iplilie ims ofmur invention it isiree uirefiixhat intormatimrbe itransnntted back to: i mm mung athuintelligence was 'eeorded flagrtetwstorase -ni'ediiml lt V s ponibie howeuer, 'tm utnize ourinventionior' nthet wboscfl mreim-theindications; ap neari'ng irom nmeto time on the iridicatorgmay oe'mansmd into permutationail signals vayo! recpondi'ngto an inquiry: in mean neat of our as h'ere'in 'disclosecl 'it is arranged to firctreeord on seeondary 'storageg' .uch as the storage medium 2, a compieterecor'd 1. code signals representing the current settings a! all indicators. These may then be read out at V111 bymreedtn bead H for the purpose ioi key 8 mcheck'heoh transmitter; -*Recording ,on the 1 m recoxdapoth l -is nerformed byrmeamv f imm rsing head ml 0 a centerrtapped connefled-to1a B:-scurce m," The We ontaidetermina eief the :rLe-

eyau is'held aeiosediiorionge'r thanicnp ggcoia cfli'diiig ha lame e'fa'irlfi'ed' throirgh ample to respectively-- inherent an des m tates 1P" soc ety which prefei'hfilyiqfthepehtde' type-' The cathodes; as'well' 'as the suppressor gfid's or these tubes; ma begieundeqs r e= ereengrmgm w a suitable ii'tpsitivepotential applied theieto throtighfiiasistdhfifi and coniieetiohs fragrance? to the 4-3 source-terminal. *The trol grids for tubes F and G are both bias'ed{-to-= eat-ctr; say -by connectionsthree resisters nma- -30 v; source terminal" 'A- tive' -eoht1 o1 pulse may he applied tothe entre? gIiKi Of eIthG? 011e otthe tubes E"afid i ,fbfltfli btj both togetherftherehyto' giveboisirity' significance tdthemagneti'zing' 'efi'ect of the mar-m ga head"lfl.

neeordmg ot the check-back signaiq isaeeeni f plished by operati'on ofa checi=baclkey as W i? may beeperated at Wi11.""This" keyfwhemelesedd feeds operating current from a batterffl to tlfe ing of relay 3? an causes l 9 s mo abl contacts" llairid" I] to close "against statitfiai'y frontcontacts; I While relay-v 3-2-1 is operated -the Uepulses--' (mark? sign'als' mm are prevented from're'aehihg the-left hsmii of'the gatetubes fl and 43. w' r-he-"irontco tactc associated :with movable contacts were indiviilltw ally. connected through cable momma-gimme of respectivelydifierehtamplifier-s11:- 'Th'ese plifiers reach havean input circuitiFl'la 1 which is individual to a connection fr'omt a 'r esp'e'ctiv'e one of the: brush sets 11-1-11 5 "05 The positive-pulses which" are derived' from thti 5=stag-= counting; ring 23", and -whicifiara" through 'a'ny ot the segmentsiof the commutatbi I3 on which briishesi 1 4 and 11 i i may -resty hre now inverted .by the amplifiers 2| and beconiinegative control puise'sas applied 'tb' the i'ef controi gridssin tube 8 and fitforz armrest-mew caters. Tubes Sand? arel selected sequehiiillii in accordance with the eperation of thefl stai counting ringvk-l, the same "as when' 'utiii-zing 'thc: 5 message signals from primary storagetor indiea tor settingpurposes: "As ceuntiiig flirg Za glyco through cycle it" delivers: a positive -ptflsrte the movableeontactsl0: to the control grids the left side of gate-tubes 48: "The pqlflsai so appiiedarenegative and partiaHy'ioIocE'1ihcD gate tubes". But only onezot them is fuBy-bIockecEfl any one such ajsiwhen'it receives a (cutct! "bias on -its right hane'ig'rid nuriig tae time of one ceu'nt iin' the? -sta'ge':eountiiig ri1g 22 The =recordingo check-back signals track of recordmg "member '2 may e; anypart' of the-revolution cyele- "theinstant' whenkey 3 8 "is: :cldsedJ Thie -correct 5 linear msitienaiong tfietraehtvill be auterlzmti-""= cailyfidetermined by the: functioning cr me-gap reset puis, e tcircuitfincluding wbee'P than? by thewperation of 'thecountirig- 11 tion at s-it should be to insure making-"a commie record Qf all indicator settings) the repeated cheek-back stgnais will be'merew of those that precededthein? m mtg 'tlie a may he-- he1d=c1osed during severar-revohifiibiis the ma ne ic recording medium i withiiii 'atri mentito the operation of the s'ysteml' acces conductors in cable 3|, thence through a mov-.

able contact 4| of relay 32, through a capacitor 45 andthrough a resistor 46 to a 100v. source m al- Y [Between capacitor 45 and resistor 46 there are control grids to be biased one way or another in three tubes, A, C and D, these being the righthand grids of tubes A and D and grid Cl in tube C. Tube ,A represents a delay circuit which is tripped only in response to the application thereto by tube S or by one of tubes 43 of a positive pulse representing a space element of the code signal, In the absence of a space pulse, tube D functions to control tube G so as to record a m rkpulse.

fMarlc-pulse recording of check-back signals .Tube D isv a twin triode which. is normally blocked on its right-hand side and is normally conductive on its left-hand side. In order for thetube to function in the transmission of a mark signal for control of tube G, both of its triode sections must be simultaneouslycut ofl. When this occurs tube G, which is normally nonconductive, will then become momentarily conductive. and will app y a recording pulse to the recording head for fixing a spot of magnetization of proper polarity on the record track 2 representinga mark element of a code signal. This operation results from the utilization of a synchronizing signal for controlling tube 3 as follows: 7

- The synchronizing pulses V are applied through contact-41 0f operated relay 32 directly to the rightehand grid of tube B and prior to .the synchronizing pulse output from tube 1, the latter having a delayed effect upon the stepping of the counting ring 23. The space signal pulses which manate originally from counting ring 23 and traverse brushes l4. and I to the amplifiers 2| (whereat they are inverted) then apply their controls to the left-hand grid of tube S an instant laterthan when tube.B responds to the synchrozinspulses.

Tubes A and B operate as one-shot. multivibratorsj, Their time constants for restoration after being triggered may be substantially the same At any rate, allowance being made for thedelay action of the delay tube H, if tubes- A and B are both triggered, tube B is arranged.

to recover its normally conductive state on its right side while tube A is still blocked on its left potential therein is low and holds the right-hand grid in tube D at a cut-off bias. In this case tube D is enabled to be completely blocked by a negative pulse through capacitor 53 and applied to its left-hand grid. Tube G then receives a positive control pulse on its No. lgrid and on being driven conductive its space path current I also traverses the half-winding of recording head l0 approximately for recording a mark pulse.

Space-pulse recording of check-back signals It was mentioned above that the space pulse Z, as derived from one of the tubes S or 43, traverses capacitor 45 when relay -32 is operated, and is applied to certain grids in tubes A, C and D. The eifect of this pulse upon tubeA is simply to trigger it and to allow it to restore. itself after a certain time lapse. But tube A is depended upon to prolong the effect of the space signal so that it will overlap the instant of restoration of tube B to the normally blocked condition on its leftside. v I

When tube B restores itself to normalcy it delivers a positive differentiation pulse through capacitor 55 to grid C3 in tube C. This occurs while grid CI in tube 0 is beingheld positive, which is durin the periodof the triggered state of tube A. Hence tube C is now driven toaconducti ve state and gates the space pulse (with some delay) as a negative signal to be applied to the control grid of tube E.

Tube E is normally conductive, but is blocked by thelast mentioned negative signal. In consequence tube F receives a positive pulse on, its #1 grid and becomes conductive, thus forming an electronic circuit closure for exciting the halfwinding in recording head Ill suitably for recording a space-element of the code signal.

Itwill be noted that when tube A is triggered for recordin a space signal its so-called pulse-,

stretching period" commences before andends. after the moment when tube B restores itself to;

normal. This mode of operation effectively prevents a gating action in tube D when recording a space pulse. Furthermore, since the differentiated pulses delivered by tube 3 upon restoring side. 'Ihe high potential on the left-hand anode intube A now holds the right-hand grid in tube Data bias level such as to maintain conductance on its, right side. Therefore, in the presence of' a space signal, tube D will not be completely blocked upon application to its left-hand grid of a differentiated negative pulse II from the righthand anode of tube B when the right-hand section of the latter recovers its normally conductive state. 1

The preceding paragraph explains how, despite he periodic tri gering of tube B in response to every synchronizin pulse, the useful eiiect of triggering upon tube D is. obtained only in the absence of a trig ring of tube A, as when the space signal is applied thereto. This .follows from the fact that when no space signal triggering of tube A occurs, the left hand anode ziabe1ed U, the sameas 'on the itself to normal are applied positively to grid C3 of tube C and negatively to the left-hand grid of tube D, and since these pulses are delivered simultaneously, it follows that either a space.

signal or a mark signal will be recorded at every recording spot along the path of the recording,

medium 2, and that the identical spot win he magnetized regardless of the polarity of the recording head.

Thus the check-back recording circuit, as shown in Fig. 2 and as describedabove, is effective to record all five code elements of each code signal representing the current setting of an indicator, each code signal being composed of three marking elements and two spacing elements.

And yet the space signals as identifiedby the standing of brushes l4 and IS on certain adjacent segments of commutator l3 are alone sufiicent to determine the code signal pattern. The

elements which are not space signals must be mark signals.

The timing of controls Fig. 5 shows a number of graphs representing pulse times incident to the operation of themtire system. A typical example is given of'read- 5 mg a permutational code, or message," from This graph is the primary storage record 3.

circuit diagram ass ss s. tha tho-M n o is. twill be noted v that ,there i's a certain "delay in heloiitnutl from the" I! as comparedfwitl l he' actual time or reading the record under, a. oanning'operatlon of the reading head 9. .elayfisre'presented'as'a time interyal jti'. The ynchronizingYpulses as'shown in Graph V are ,ppliedto vtulr'ies B and H, without delay, but tube I introduces delay equal to tiin thedeli'veryof lo'd W b o p lied, to he. counting ring 23.

Graph X r pr t pp n pulse w h s .pplied to the 7-stag'ecounter'22 after adeIayJ re 'i'odjlabeled 't withres'pect to the countin of the'counting 23. The. delayperiod l isihtrpduced as a; function of the delaytube whlchcontrols cathodefollower t ners. "Each thatftube 'K is rend'ei'ed conductiyia con} misuse X is. app iodft tho t so o n 18 mit ena e r m ,onos o's toon hefl steps. jhoyiveveif, have a persistent effect. own o a 1111 oy l i. t e. oo nt ng rin in 'rdenthatonejfafter another of the S and a shall remain standing iii-ii partially. blockegli' ondition i'orj'selective' response to successive -unit code signals: This standin condition'is nio o od bw fi rap Y for o t s 'oi 'e stagefcounter.

Z, and graph U arethe same except for r o 'o i s f ei P y mo ent 'illustrati'vely the-reading of a code signal Graph N represents the applieation If seam pulses delivered as output from eft' side of tube A injthej presence of a. space ignal as used ior check-iback recording, v The lura'tion it; of this' positiye'puls'e is one which it to] straddle a control pulse derived mm thfltermination'of the triggered state i v u'f iB." "Therefore; in the presence of the checks'lg'nal jtubel) is preventedfifrom bein painted to deliyer a mark pulse when tube Ci 5' driV'en' conductive .ior the delivery 'of a space lcr s capacitor ilundencontrol or tubers, ecomes being ap l do h o ro rid o v he lett-handtriode section of tube D. The posi we are small in comparison with the legatiyefpulses due to the cathode biaswhich" s normally. on the left-hand grid r ube. D; These positive pulses haveno nert a d .a'are controlling and cause tube T'D to re entirely cut" off in 1 the absence of a space soh m m r-out the os l o t n o nose: iveand '.p' sa1 ve.,pu1ses to s d C i ub 1%"r s ver o s o ar er a do o'vo o it thea ers of the pulse-stretching" :ontrol as above described and being effective, j

or recording space signals on the secondary. image time 11; will'bere'mernbered thatthese :pace pulses-are negative as delivered across mpalcibor'bl t'o tube E and they occur after a [clay interval is as measured fromv the syn'- j ai se j i re 5.

14: b ne at v -1 i aoo ura whoatube a oooirilotodl its fi loe tre iinvb rio a deiyeisfa ative pu s o the enjh d e of time D therebyflto block thiso triode, ect'" n the right liaridjs'ectionhein already bloc res l ant; peration s to el e P9 i ti; p l e h ugh capacitor 5! to he cont ol'i g' idf of wh G and o oausot reoorq oaoia mange,

signal. 7

R on l tionl,

It i e p a to h eskil od n the art, that t i m erzoi indi a oroto eincluded in a system such as wehave described may-be r; ohsro ter than he; num r se en, which: was used merely ior purposes of illustration. Any number ofhrecordingspaces on the1nagnetie, storage medium may be provided withinreason ablelimits for individual identificationand lection of difierent indicator unitslg more, if code, signals having. more than; 5. e1er ments'wereto be employed, then the nun bc selectable setting 'positions ior the indicator be greater than'10. Still again, it is teas one .s roo of sy c r n in pulses.

setting controls without any intermediate store age. 'Thus the'appreciablejtime that 'is'reeuiredf to setan indicator electro-mechanically from one position of orientation to another hinde'rance to the signal scanning speed/ The setting operation for different indicators will oftentimes be overlapping during the scanning of a message train from the storage unit 3; change of record such as maybe introduced "by means of new ,recordingsapplied to the recording head" 8 will result in an immediately iollowing read-out of c ntrol signalsefor resetting the.ap-..

propriate ,indicators.

Considerable modification of the electronctube a. components and their circuitparameters for adaptation of our systemic ,iifier ntrequires. t q a v readil b m de y ho e killedi the a t but ,w t tdepor ms om the spirit; of the'invention. We do not, therefore to limit thescope of the claims merely to the s r ti mb dime t b roints wn an do. scribed.

n v i o ii n i a r: s teble-sto, different positions to manifest the significance g; differentcharacter ode isna sa commutatorl, and-brush arrangement operatiyelyfi-coupled, to

the indicator-i for signiryi eits; orientation. .a

comparator and a step by-step setting mocha-i; nisn operatively associated withthezindicator, a c. cyclically operable itemlstorage devicehav-inga magr etic recording track, means for serially rte-1* cording the character code signals on said track.

read-out means including an electronic counting ring; for serially and repetitively applying individual character ,code signals to said comparator, a synchronizer under control of the cyclic tion of said storageidevice; synchronizing responsive means for coordinating the function- 7 in o .7 h ..coinpareiorv with a articular char aoter- ,;reoordinsmnsition.on the or said 16 to utilize aplurality of message storage tracks". on a rotatable drum, each traok'being 'spa gcj by a separate reading headLB L, Thus thecontroli of diirerent groups of. indicator unitsmay be; made concurrently even. though, therfjis only} I 15" storage device, and means for causing said comparator to initiate a step to be taken by its assoacters representing the data stored in the prlmary record track, electronic translating means under control of said reading devices for causing each of said indicators to move step-by-step into a position to display a character representing a magnetically recorded item to which it pertains, the steps of said indicator movements being one per revolution of said medium, means for terminating the stepping movements of each indicator when its indication is brought into agreement with the correlatively stored item, and check-back means operable at will for injecting into said secondary record track coded items corresponding to the setting of each indicator 3. A data posting system comprising a plurality of indicators each settable to display'difierent numerals or other characters according to selection, a magnetic record medium having a record track for coded data characters respectively to be displayed on said indicators, the codes for said characters being disposed serially on a single secondjtrack in conforr'nity with the current track, a source of synchronizing pulses disposed serially on another track on the record medium,

read-out devices operatively disposed with respect 1 code, and code translating means responsive to joint control by said read-out devices and said synchronizing means for producing step-by-s'tep setting movements in each indicator until agreement is reached between its character indication and themeaning of the corresponding character that is read out from the record medium.

4. A system according to claim 3 and including in the last said means a comparator'and a segmented commutator-and-brush arrangement operatively associated with the rotor of each indicator, the segments of said commutator on which a plurality of brushes currently rest being indicative of the orientation of that indicator, said comparator being operative to sense the coincidence of a mark element when applied thereto from the read-out, and a correlative space element of a code the pattern of which is determined by the brush positions with respect to said commutator.

5. A system according to claim 4 and including a second record track for coded data characters on said magnetic record medium, recording meam operatively disposed with respect to this second track, a signalling device under control of said commutator for transmitting signals to said recording means, and means operable at willfor pulses are absent;

initiating such operation of said signalling device setting of each indicator, said last named means including the means controlled by'the synchropulses for activating the segments of the commutators of the indicators successively to control the recordings of the code signals on said second record track for'coded data characters.

6. Ina system of the class described, that is, where transmitted code signals are used to control an indicator setting device, a commutator-.

and-brush device operable in conjunction with the orientation of the indicator for deriving a code pattern which defines the indicators instant setting, a comparator arranged and adapted to sense the coincident application thereto or a mark element and a space eleinent, one of'said elements being amongst those of said code signals which are progressively received, and the other of said elements being amongst those of said code pattern, means including circuit connections from said comparator to said setting device whereby the setting device is caused to function in response to the sensing of said markspace coincidence, and means for causing progressive and repetitive tests to be made by the comparator with respect to each comparable element of the received code signal until the reorientation of said indicator cancels the condition of said mark-space coincidence throughout a complete scanning of said code pattern.

7. The combination according to clairn' 6 and including a magnetic storage medium for transmitting said code signals repetitively.

8. In a system for composing permutation code signals representative of the orientation or a drum-type indicator, a commutator-and-brush device operably associated with said indicator, means for applying pulses to certain segments of said device in one predetermined sequence,

means for simultaneously applying the same pulses to other segments of said device in editferent predetermined sequence respecting their serial arrangement, means responsive to the pickup of said pulses whenever conveyed thereto by virtue of brush contact with a segment to'which the pulse is applied, a source of periodic pulses,

representative of code elements of a sense contra to the sense of the first said pulses, andcode composing means operable under control of said responsive means to dovetail together a fixed-number of code elements of each respective sensebut in different patterns which depend upon; the v standing of brushes or particular segments of said device, said code composing means being arranged and adapted to synthesize each permutation of code elements by inclusion therein or the brushtraversing pulses wherever they occur in the sequence of pulse periods, and by substitution or the pulses of opposite sense'when the pick-up 9. The combination according to claim 8 and including a magnetic recorder for storing the output from said code composing means.

10. The combination according to claim 8 and and including an electronic counting ring operable at the cadence vof said periodic pulses, said counting ring having as one of its functions to control the rate of sequential application of pulses to different segments of said device.

11. The combination according to claim 10 and includinga second counting ring arranged for stage-by-stage counting at a rate equal to com-' plete cycles of counting by the first said ring, this second ring being operable to successively 1 7 activate difierent ones 01' a. plurality of said pickup pulse responsive means which are operatively associated with different ones respectively of a plurality of indicators and their commutatorand-brush devices. 5

JOSEPH C. MARSHALL. JOHN J. CONNOLLY.

REFERENCES CITED The following references are of record in the 10 file of this patent:

Number UNITED STATES PATENTS Name Date Bellamy et a1 Oct. 26, 1937 Gardner Oct. 11, 1938 May et a1 May 28, 1940 Hicks Dec. 10, 1940 Haselton et a1 Nov. 24, 1942 Hartley et a1. Apr. 2, 1946 

